Many computer vision problems involve assigning a label to each pixel within an image. These labels may indicate whether the pixel is part of the background or foreground (e.g. for image segmentation) or whether the pixel is part of an electronic ink stroke or not (e.g. for electronic ink recognition). Depending on the application, the label may be selected from two possible labels or from a larger number of labels.
A number of techniques have been developed and applied to such computer vision problems, such as graph cut, tree-reweighted message passing (TRW), belief propagation (BP), iterated conditional modes (ICM) and simulated annealing (SA).